The invention resides in a roughness scanner particularly for industrial applications, but also for laboratory use.
Roughness scanners are used to determine the roughness of a surface. To this end, the roughness scanner includes a skid of a size of a few millimeters which is in contact with the workpiece. A very fine scanner needle extends through an opening in the skid and into contact with the workpiece surface. The vibrations of the scanner needle caused by the roughness of the surface during the skid over the workpiece are picked up just like in a record player and converted into electrical signals and are evaluated for determining a characteristic roughness value.
The scanner needle and the skid are very small components which are also very sensitive. The opening through which the scanner needle extends is, for example, only one millimeter wide or even smaller. Although it is not in compliance with the measuring specifications, the roughness scanners may at times come into contact with oily workpiece surfaces. Such problems occur mainly during use in connection with manufacturing equipment. The oil present on the workpiece surface then accumulates around the scanner needle in the skid opening whereby it is slowly transported by the vibrations of the needle into interior of the roughness scanner. However, because of its viscosity the oil influences the measurements undesirably, so that the measuring results of such a roughness scanner are no longer reliable. It must therefore be flushed out which, because of the small dimensions of the roughness scanner requires special skills. Furthermore, it is difficult to remove solvent or flushing medium from the roughness scanner. They adhere, for example, to the surfaces areas between the skid and the scanner needle because of capillary effects. A visual examination whether the gap around the scanner needle is free from solvents or flushing liquids, washing liquids, oils or similar media, is impossible without magnifier and is even with a magnifier not reliably possible.
It is therefore the object of the present invention to provide a roughness scanner, which is usable reliably also in connection with manufacturing procedures.